NEW YORK, July 11 (Reuters) - HSBC Holdings Plc and UBS Group AG have each agreed to pay $14 million to settle private U.S. litigation accusing them of rigging an interest rate benchmark used in the $483 trillion derivatives market.

The preliminary settlements were disclosed in filings on Tuesday in the U.S. District Court in Manhattan, and require a judge’s approval. They boost the total payout from 10 settling banks to $408.5 million. HSBC and UBS denied wrongdoing.

Several pension funds and municipalities had accused 14 banks of conspiring to rig the ISDAfix benchmark for their own gain from at least 2009 to 2012.

The private litigation is among many lawsuits in the Manhattan court accusing banks of conspiring to rig rate benchmarks, securities prices or commodities prices.

The case is Alaska Electrical Pension Fund et al v. Bank of America Corp et al, U.S. District Court, Southern District of New York, No. 14-07126. (Reporting by Jonathan Stempel in New York; Editing by Phil Berlowitz)